A type of fuel reforming system known from the prior-art comprises with a membrane-type hydrogen generator which separates hydrogen from a reformate gas using a hydrogen permeable membrane (membrane hydrogen separator). Tokkai 2001-135336 published by the Japanese Patent Office in 2001 discloses a fuel reforming system using this type of membrane-type hydrogen generator.
The strength of the hydrogen permeable membrane, and in particular, the strength of a metallic hydrogen permeable membrane is reduced during permeation of hydrogen. This phenomenon is known as hydrogen embrittlement. Consequently the fuel reforming system must supply hydrogen to the hydrogen permeable membrane taking such hydrogen embrittlement into account. Hydrogen embrittlement tends to occur at low temperatures in a metal membrane hydrogen separator such as a palladium membrane or a palladium alloy membrane.